Various known gaming systems display three-dimensional images to players. Certain of these known gaming systems generate virtual three-dimensional images and display those virtual three-dimensional images on a single display screen. Since these known gaming systems employ only a single display screen to display these virtual three-dimensional images, these virtual three-dimensional images have simulated depth, not actual depth. These known gaming systems generate such virtual three dimensional images using a variety of techniques, such as shading, highlighting, and/or perspective techniques, to generate an image having a perceived depth (from a player's point of view) when displayed on the single display device. These virtual three-dimensional images thus cause the human eye to perceive the virtual three-dimensional images as having depth when in fact the images have no actual depth.
Other known gaming systems generate three-dimensional images using a display device including two or more aligned display screens each separated by a predetermined distance. The use of such multiple aligned display screens enables these known gaming systems to generate three-dimensional images having actual depth. More specifically, these known gaming systems in part use the predetermined distances between the display screens to add depth to images such that they are displayed in three actual dimensions. One such known gaming system generates and displays an image in three actual dimensions on a display device having two aligned display screens by displaying that image on each of the two display screens at a same distance from a horizontal reference plane and a same distance from a vertical reference plane. That is, for each portion of the image, this known gaming system displays that portion of the image: (a) on a first display screen at a first distance from the horizontal reference plane and a first distance from the vertical reference plane, and (b) on a second display screen at the first distance from the horizontal reference plane and the first distance from the vertical reference plane. The predetermined distance between the two display screens adds actual depth to the resultant image displayed by the display device; that is, the resultant image is displayed to the player in three actual dimensions. Another such known gaming system generates and displays an image in three actual dimensions on a display device having two aligned display screens by displaying different portions of that image on each of the two display screens. The predetermined distance between the two display screens adds actual depth to the resultant image displayed by the display device; that is, the portion of the image displayed on one of the display screens appears closer to the player than the portion of the image displayed on the other one of the display screens. Thus, the resultant image is displayed to the player in three actual dimensions.
While the predetermined distance between the display screens enables such known gaming systems to display images to a player in three actual dimensions, it also causes parallax artifacts to appear to the player in certain instances. More specifically, when a same image is displayed on each of two aligned display screens at a same distance from a horizontal reference plane and a same distance from a vertical reference plane, certain portions of the image displayed on a front display screen do not fall on a same line of sight of the player as the corresponding portions of the image displayed on a rear display screen. That is, depending upon the viewpoint of the player, in these instances the player typically is able to see portions of the image displayed on both of the display screens rather than a single cohesive three-dimensional image.
FIGS. 1A, 1B, 2A, 2B, 2C, 2D, and 2E illustrate an example of the problem caused by such parallax artifacts. FIG. 1A illustrates an example of one embodiment of a gaming system, which in this example is an electronic gaming machine 10 (“EGM,” as described below). EGM 10 includes a cabinet or housing 12 that houses a display device 14 and a touch screen 16. Display device 14 includes an exterior display screen 18a and an interior display screen 18b. Exterior display screen 18a and interior display screen 18b each include a display surface. EGM 10 includes a processor (not shown) configured to operate with exterior display screen 18a and interior display screen 18b to display one or more images on the display screens of exterior display screen 18a and interior display screen 18b. Exterior display screen 18a and interior display screen 18b are mounted and oriented within housing 12 such that at least one line of sight of a player, such as line of sight 20 extending from a viewpoint 11 of the player, intersects both the display surface of exterior display screen 18a and the display surface of interior display screen 18b. Display device 14 also includes a back lighting source 19 positioned behind and aligned with exterior display screen 18a and interior display screen 18b. As shown in FIG. 1A, exterior display screen 18a and interior display screen 18b are separated by a predetermined distance dbl, which is the distance from the display surface of exterior display screen 18a to the display surface of interior display screen 18b along a line perpendicular to the display surfaces of exterior display screen 18a and interior display screen 18b. 
FIG. 1B illustrates an exploded perspective view of exterior display screen 18a, interior display screen 18b, and viewpoint 11 of the player. FIG. 1B also illustrates a first reference plane 700, which is a horizontal plane in this example, and a second reference plane 800, which is a vertical plane in this example. First reference plane 700 and second reference plane 800 are defined based on the location of viewpoint 11 of the player. More specifically, in this example, viewpoint 11 of the player acts as the origin of a standard (x,y) coordinate axis, first reference plane 700 extends from the created x-axis into the display screens, and second reference plane 800 extends from the created y-axis into the display screens.
FIG. 2A illustrates a front view of interior display screen 18b as viewed from viewpoint 11 of the player, FIG. 2B illustrates a front view of exterior display screen 18a as viewed from viewpoint 11 of the player, and FIG. 2C illustrates a front view of display device 14 (which includes exterior display screen 18a and interior display screen 18b) as viewed from viewpoint 11 of the player. As shown in FIGS. 2A, 2B, and 2C, exterior display screen 18a and interior display screen 18b co-act to display resultant three-dimensional images 22, 24, and 26 on display device 14. Resultant three-dimensional images 22, 24, and 26 are identical outlines of a square.
To provide resultant images 22, 24, and 26 in three dimensions, interior display screen 18b displays image 22b (i.e., the square, as shown in FIG. 2A) and exterior display screen 18a displays image 22a (i.e., the square, as shown in FIG. 2B) at a same distance from first reference plane 700 and a same distance from second reference plane 800. For example, the bottom right corner of image 22a is displayed on exterior display screen 18a a first distance from first reference plane 700 and a second distance from second reference plane 800. Accordingly, in this example, the corresponding bottom right corner of image 22b is displayed on interior display screen 18b the first distance from first reference plane 700 and the second distance from second reference plane 800. Similarly, interior display screen 18b displays image 24b (i.e., the square, as shown in FIG. 2A) and exterior display screen 18a displays image 24a (i.e., the square, as shown in FIG. 2B) at a same distance from first reference plane 700 and a same distance from second reference plane 800, and interior display screen 18b displays image 26b (i.e., the square, as shown in FIG. 2A) and exterior display screen 18a displays image 26a (i.e., the square, as shown in FIG. 2B) at a same distance from first reference plane 700 and a same distance from second reference plane 800.
As a result, display device 14 displays resultant three-dimensional images 22, 24, and 26 (i.e., the square), as illustrated in FIG. 2C. Since both exterior display screen 18a and interior display screen 18b display the same images of the square, resultant three-dimensional images 22, 24, and 26 are formed in three actual dimensions. The depth of resultant three-dimensional images 22, 24, and 26 are equal to (or otherwise based in part on or derived from) the predetermined distance dbl that separates the display surface of exterior display screen 18a and the display surface of interior display screen 18b. However, it should be appreciated from FIGS. 2A, 2B, and 2C that as viewed from viewpoint 11 of the player, which in this example is located at the intersection of the first reference plane and the second reference plane a certain distance from the exterior display screen, the combination of: (a) the predetermined distance dbl that separates the display surface of exterior display screen 18a and the display surface of interior display screen 18b; and (b) the fact that, in this example, images 22a and 22b are displayed at a same distance from first reference plane 700 and a same distance from second reference plane 800, images 24a and 24b are displayed at a same distance from first reference plane 700 and a same distance from second reference plane 800, and images 26a and 26b are displayed at are displayed at a same distance from first reference plane 700 and a same distance from second reference plane 800 causes vertical and horizontal parallax artifacts to appear in resultant three-dimensional images 22, 24, and 26 that, from the player's point of view, distort resultant three-dimensional images 22, 24, and 26.
More specifically, as shown in FIG. 2C, as viewed from viewpoint 11 of the player: (a) each portion of image 22b displayed on interior display screen 18b appears to be closer to first reference plane 700 and second reference plane 800 than the corresponding portion of image 22a displayed on exterior display screen 18a, (b) each portion of image 24b displayed on interior display screen 18b appears to be closer to first reference plane 700 and second reference plane 800 than the corresponding portion of image 22a displayed on exterior display screen 18a, and (c) each portion of image 26b displayed on interior display screen 18b appears to be closer to first reference plane 700 and second reference plane 800 than the corresponding portion of image 26a displayed on exterior display screen 18a. Accordingly, from viewpoint 11 of the player: (a) images 22a and 22b do not co-act to form a cohesive resultant three-dimensional image, (b) images 24a and 24b do not co-act to form a cohesive resultant three-dimensional image, and (c) images 26a and 26b do not co-act to form a cohesive resultant three-dimensional image. It should be appreciated that the parallax effect in FIG. 2C is slightly enhanced for clarity. It should further be appreciated by comparing resultant three-dimensional image 24 with resultant three-dimensional images 22 and 26 that the effect of the parallax artifacts worsens the further the images are from the viewpoint of the player.
FIG. 2D more specifically illustrates the vertical component of these parallax artifacts. FIG. 2D illustrates a side diagrammic view of display device 14 in which exterior display screen 18a displays images 22a, 24a, and 26a and interior display screen 18b displays images 22b, 24b, and 26b. It should be appreciated that certain of the components of FIG. 2D are slightly enhanced for clarity. As explained above, it should be appreciated from FIG. 2D that the corresponding portions of: (a) images 22a and 22b are displayed on exterior display screen 18a and interior display screen 18b, respectively, a same distance from first reference plane 700; (b) images 24a and 24b are displayed on exterior display screen 18a and interior display screen 18b, respectively, a same distance from first reference plane 700; and (c) images 26a and 26b are displayed on exterior display screen 18a and interior display screen 18b, respectively, a same distance from first reference plane 700. For example, the corresponding bottom edges of images 22a and 22b are both located a same distance from first reference plane 700.
Line of sight 31 extends from viewpoint 11 of the player and intersects the top edge of image 22a displayed on exterior display screen 18a (i.e., the top edge of the square displayed on exterior display screen 18a in this example). Line of sight 31 does not, however, intersect the top edge of image 22b displayed on interior display screen 18b (i.e., the top edge of the square displayed on interior display screen 18b in this example). That is, the top edge of image 22a displayed on exterior display screen 18a falls on a different line of sight than the top edge of image 22b displayed on interior display screen 18b. Accordingly, in this example (and as illustrated in FIG. 2C), the player views the top edges of both image 22a displayed on exterior display screen 18a and image 22b displayed on interior display screen 18b. A similar effect exists with respect to: (a) images 22a and 22b and line of sight 32, (b) images 24a and 24b and lines of sight 33 and 34, and (c) images 26a and 26b and lines of sight 35 and 36. This vertical component of the parallax artifacts results in the player viewing a distorted resultant three-dimensional image rather than a cohesive resultant three-dimensional image.
FIG. 2E more specifically illustrates the horizontal component of these parallax artifacts. FIG. 2E illustrates a top diagrammic view of display device 14 in which exterior display screen 18a displays images 22a, 24a, and 26a and interior display screen 18b displays images 22b, 24b, and 26b. It should be appreciated that certain of the components of FIG. 2E are slightly enhanced for clarity. As explained above, it should be appreciated from FIG. 2E that the corresponding portions of: (a) images 22a and 22b are displayed on exterior display screen 18a and interior display screen 18b, respectively, a same distance from second reference plane 800; (b) images 24a and 24b are displayed on exterior display screen 18a and interior display screen 18b, respectively, a same distance from second reference plane 800; and (c) 26a and 26b are displayed on exterior display screen 18a and interior display screen 18b, respectively, a same distance from second reference plane 800. For example, the corresponding right edges of images 22a and 22b are both located a same distance from second reference plane 800.
Line of sight 41 extends from viewpoint 11 of the player and intersects the left edge of image 22a displayed on exterior display screen 18a (i.e., the left edge of the square displayed on exterior display screen 18a in this example). Line of sight 41 does not, however, intersect the left edge of image 22b displayed on interior display screen 18b (i.e., the left edge of the square displayed on interior display screen 18b in this example). That is, the left edge of image 22a displayed on exterior display screen 18a falls on a different line of sight than the left edge of image 22b displayed on interior display screen 18b. Accordingly, in this example (and as illustrated in FIG. 2C), the player views the left edges of both image 22a displayed on exterior display screen 18a and image 22b displayed on interior display screen 18b. A similar effect exists with respect to: (a) images 22a and 22b and line of sight 42, (b) images 24a and 24b and lines of sight 43 and 44, and (c) images 26a and 26b and lines of sight 45 and 46. This horizontal component of the parallax artifacts results in the player viewing a distorted resultant three-dimensional image rather than a cohesive resultant three-dimensional image.
One proposed solution to reduce and/or eliminate these parallax artifacts involves feathering, softening, or blurring the edges of the image displayed on the interior or rear display screen (i.e., the display screen positioned further from the player). This makes it more difficult for a player to view the edges of the image displayed on the rear display screen. Another proposed solution to reduce and/or eliminate these parallax artifacts involves choking or scaling down the size of the image displayed on the interior display screen. This reduces the appearance of parallax artifacts relatively close to the viewpoint of the player. Yet another proposed solution to reduce and/or eliminate these parallax artifacts involves both feathering, softening, or blurring the edges of and choking the size of the image displayed on the interior display screen. These proposed solutions have multiple significant drawbacks. Feathering, softening, or blurring the edges of the image displayed on the interior display screen requires an artist to create such an image and the gaming system to render and display that image, which uses a relatively large amount of computing resources. Additionally, feathering, softening, or blurring the edges of the image displayed on the interior display screen may somewhat reduce the effect of the parallax artifacts, but does not completely eliminate the parallax artifacts. Similarly, choking or scaling down the size of the image displayed on the interior display screen also requires a relatively large amount of computing resources to scale that image down and to render that image. Additionally, choking or scaling down the size of that image somewhat reduces the appearance of parallax artifacts relatively close to the viewpoint of the player, but does not completely eliminate the appearance of parallax artifacts, especially with respect to images displayed relatively far from the player's viewpoint. That is, this proposed solution assumes that the error caused by these parallax artifacts is constant, no matter where the three-dimensional images are displayed in relation to the viewpoint of the player, when in practice the parallax artifacts become more significant and apparent to players as the three-dimensional images are displayed further from the player's viewpoint.
Accordingly, there is a continuing need for a gaming system including a display device having multiple display screens and that is configured to generate and display images in three actual dimensions while reducing or eliminating the appearance of parallax artifacts.